Environmental barrier coatings (EBCs) are often utilized to protect engine components for harsh conditions present in high temperature engine environments. EBCs can provide a dense, hermetic seal against the corrosive gases in the hot combustion environment and can help prevent dimensional changes in the component due to oxidation and volatilization processes. Unfortunately, there can be some undesirable issues associated with standard, industrial coating processes such as plasma spray and vapor deposition (i.e. chemical vapor deposition, CVD, and electron beam physical vapor deposition, EBPVD) currently used to apply EBCs. More specifically, plasma spray process can typically result in the EBC having a surface roughness of greater than 200 micro inch (about 5 micrometers) Ra, which can be undesirable when factoring in aerodynamic design considerations in advanced turbine engines.
Accordingly, there remains a need for methods for improving the surface roughness of plasma sprayed EBCs.